Write-Up: Fuel Pump/Tank Sending Unit Replacement

charlieRobinson wrote:

I tested the module. Pulled the pump out and tested it and it worked fine.

Wired it back up and the Riv is running again. 2nd time this has happened no idea why. everything is perfect when i pull it and dissect it.  

I can't remember if you did a rewire or not. If you didn't, maybe do one? If you did, maybe that's to blame?

Does anyone think replacing the entire pump and housing assembly is worthwhile? There's a big difference between the $37 fuel pump Rock Auto sells and the $195 AC Delco pump and housing

Jack the R wrote:

Does anyone think replacing the entire pump and housing assembly is worthwhile?  There's a big difference between the $37 fuel pump Rock Auto sells and the $195 AC Delco pump and housing

Only things I can think of are (1) be sure to clean or replace the fuel level sender and bend the arm the right way - details in the service manual and (2) replacing the pump alone is not a bad idea, as likely as not you'll get a better pump.

That said, the Carter pump that the GM dealer installed in my Riv more than a decade ago is  still running fine.  I did have to promise the parts guy not to run with less than 1/4 tank ha ha.

If you believe what Tom Taylor says in his fuel pump writeup the cheapest pumps RockAuto sells should perform satisfactorily.  If that is the case it'd require a side by side bench teardown to figure out the difference.

It looks like Intense's Walbro with the venturi setup is the one to get for the L67 - Link

Turtleman switched to a racetronix, but I don't know which one.

edit - Turtleman's racetronix was a modified Walbro 255. I can't tell if this is still available or not.

An exchange I've been having with Turtleman, very enlightening -

Quote :

Turtleman - Up until the FGT transformation i was using the racetronix as sold by prj. Twas a walbro 255 modified with the venturi feed port. Served me very well. I don't know what current availability is on them.


Jack the R - What are you running now?

Turtleman - Now I'm using the Deatschwerks 400. You can get them with the venturi feed too.
It's a larger body so very tight fit in the bucket - I had to remove the rubber isolator.
It sucks nearly twice the current as my walbro did so need to make sure the wiring can handle that. Mine legit takes like 30 amps under full boost

Jack the R - I've ordered Intense's Walbro with the hotwire fuel harness they sell. I think it's supposed to be the Casper Electronics fuel harness. Is that what you're using? I found a Bonneville thread that said the Casper harness was the best one.

Turtleman - Uh well I think the riv is a totally different animal in terms of fuel pump wiring than a w-body.
We have that PWM module in the trunk that runs the pump. The w-body has like a resistor circuit to step down power (that tends to fail).

I haven't seen one of these casper harnesses up close but I'm figuring the part of the harness you can probably use is the part that plugs into the actual in-tank assembly and then I'd splice the other end of those wires to that module we have. (likely somewhere near the connectors underneath the car close to the rear driver side seat where the harnesses pass through)

You'll see that the wires coming out of the PWM module are heavy gauge good wires. Where it goes wrong is the ground that feeds that module and mainly where those wires transition to the outside of the car (at least on the 95-97) it goes through a connector and then it's shit wire to the pump. You'd be basically wanting to eliminate that portion of the wiring. 98-99 Wiring is a lot more concise.

Jack the R - I read about the Casper harness in a Bonneville thread. As far as I know it runs an extra wire up to the alternator to pick up extra juice for the pump. I'm going to hope they make a generic harness that will work across H, W, and G platforms and not specific harnesses for H and W. We'll see when it gets here.


Turtleman - If the wiring harness runs a new wire all the way to the alternator then it effectively eliminates the PWM speed controller in the trunk since it works on the positive side. I wouldn't wanna do that in a street driven car since it would then run the pump at full speed at the time. It would shorten the life of the pump and maybe heat the fuel up a little. Not the end of the world but there's no reason at all to get rid of it. It's very reliable unlike the w-body garbage.
If you want the benefit of that wire upgrade and keep the speed controller, I'd run the new wire from the alternator or a main power artery (i'd just go to the battery since it's close) to the relay for the fuel pump instead of to the pump (like the new harness presumably comes), and then basically replace the two fuel pump wires going from the speed controller in the trunk to the pump, and finally, run a new dedicated ground supply for the speed controller. That would take care of all wiring improvement matters.

I wish I could find some new terminals for the speed controller so I could insert brand new terminals on my own wire run but I don't know where to get any. So I just solder or crimp to new wire. Soldering is difficult because of the large 12ish gauge wire coming out of the speed controller. You need a lot of heat to get good wicking. I just used like a barrel crimp.

My next question is, will the Walbro work with the existing wiring harness? I want to upgrade the wiring but I may want to drive the car while I'm figuring out what I need to do.

My God, that lock ring! How does GM get away with doing this crap? You gotta push it down and turn it at the same time, like an aspirin bottle. The special wrench is $300! But you can get it on eBay for half that used. I'm seeing some "universal" ones on Amazon for $25, maybe one of those will work. I'm not having a lot of luck banging mine out with a brass drift. Not too pleased here.

I've fallen back on the "pry up the tabs" technique, but I can't get to the tab under the fuel lines. Did anyone get that one?

One thing that has helped was grinding a notch into my brass drift so it doesn't pop off the lock ring so easily.

Every time I've done mine, I used a flat screwdriver or flat punch and hit the ring around from like the side with a hammer. Works fine for me

I finally got mine, I just had to upgrade to a bigger hammer.

Here's what I ended up using -



Brass drift with notch ground into the end.



Heavy hammer.

I had four of the five locking tabs bent up a little too. I don't know if that's necessary or not with the big hammer. It was still pretty tough to get out of the indent with the big hammer.

That looks like a genuine B. F. Hammer.

albertj wrote:

That looks like a genuine B. F. Hammer.

I don't know what that is. I think it was home made.

Back on this job.

I had a little trouble with this blue key because I couldn't tell whether it pulled up or flipped over.  It pulls up.  Here's a pic for those who like to know what they're with -



Next problem I ran into, Walbro doesn't include the crimps for the wiring harness anymore, even though it says they do on the Intense website.    Be warned.

And the next problem - I melted this tube with my heat gun trying to soften it up enough to pull it off.  I think there's enough left over to work with.  

The flex straw tube doesn't melt easily.  I heated it and it came off without issue.



I'm having a hard time pulling the pump from the cannister -



I can stretch the rubber sheath it's in but the sheath doesn't pop loose.  What is the trick to getting the pump out?

the little plastic line I just cut off as close to the nipple as possible and then maybe heat it up a little and push it onto the new pump nipple. Yeah heating that up doesn't help get it off. Heat can help with the main hose a bit but you gotta be very cautious with that too. It will form pinhole leaks if its heated too much and moved. That happened to me before and I didn't see it.

You can buy the terminals at you local pepboys or order online for cheap. The factory plugs are the little 140 series terminals. If you upgrade to what most new pump assemblies come with, where they have you cut off your original plug and install a new one onto the wiring, those are 280 terminals.
Jack the R, what do you actually have to work with? Did they just give you a walbro plug with just bare wires at the other end?

Getting the pump out of the bucket, You can probably see that it must go upward out of the bucket since the rubber isolator has those orientation tabs at the top. That raised lip on the rubber right against the bottom of the bucket is what keeps it down. I don't remember having a lot of trouble with that but i'd just let it sit in hot water to try to get the rubber to soften and then push the bucket down with the bottom against a surface until something moves. Either the pump slides through the rubber or the rubber pops through the bucket.

JR,
I wish I saved my old pump assembly for you. You could have cannibalized all the parts you need from it.

I replaced my pump assembly with a NOS one from Ebay many years ago. I had won it with a $75.00 bid with free shipping.
Very good deal that I just put on my shelf in case I needed it in the future.
Well, my fuel tank needed replacement, a couple of years later, due to the corrosion of the metal part of the lock ring that just rotted away from the plastic tank and caused an EVAP leak and code.
So when I had the tank replaced I also had them install the new pump assembly.

I remember thinking at the time that I should save the older working pump, just in case, but by the time I went back to the shop to get the old tank and pump it had already been picked up by the people that picked up his recyclables. Sorry.

Oh that reminds me, I have a whole roll of clear tubing I got for the venturi hose. I can send you some. I have some various size corrugated hoses if you want me check out but I thought they usually give you those with any pump kits

Here's a couple more issues.  I bought this Herko fuel level sending unit.  It's supposed to fit the 97 Riviera but as you can see the clip is totally different -



So much for that.  I'm still looking for a new sending unit or sensor.  I can't imagine putting this back together with the disfunctional GM part after doing all this work.

I'm also looking for a filter for the cannister -



I think this is for the pump.  Is it possible to get the filter for the cannister seperately.  

How does the cannister filter come off on a 97?  It's different than what's pictured in the series I thread.

turtleman wrote:

the little plastic line I just cut off as close to the nipple as possible and then maybe heat it up a little and push it onto the new pump nipple. Yeah heating that up doesn't help get it off. Heat can help with the main hose a bit but you gotta be very cautious with that too. It will form pinhole leaks if its heated too much and moved. That happened to me before and I didn't see it.

Oh well. The Walbro had a replacement main hose so that isn't a problem. I wouldn't mind replacing the little plastic line if I can figure out how to remove the other end. I'll have to look at it again.

turtleman wrote:

Jack the R, what do you actually have to work with? Did they just give you a walbro plug with just bare wires at the other end?

Yes, Walbro plug with bare wires.

I've got an O'reilly's and a NAPA in town.

turtleman wrote:

Getting the pump out of the bucket, You can probably see that it must go upward out of the bucket since the rubber isolator has those orientation tabs at the top. That raised lip on the rubber right against the bottom of the bucket is what keeps it down. I don't remember having a lot of trouble with that but i'd just let it sit in hot water to try to get the rubber to soften and then push the bucket down with the bottom against a surface until something moves. Either the pump slides through the rubber or the rubber pops through the bucket.

I was thinking the pump+rubber sleeve pulled out the bottom. Maybe after a quarter turn it would "unlock." I'll give your way a try.

Making progress.  The pump is out of the cannister, and I found a different Herko fuel level sending unit that has the right clips on it - New Herko Fuel Level Sensor FC47 For Fuel Pump Module E3938M

So now I'm down to the filter for the cannister, the crimps, and maybe the little black tube.

It looks like the pump can't go down all the way in the sleeve because of these fins on the bottom.  Is that o.k.?

I'm not getting anywhere with the silly straw.  I've heated it up good but it's not even going over the first rib of the cannister nipple.  The nipple on the pump is smaller and I think I can get the straw on that, but I'm not confident the pump won't blow it off.  I'd be happy to buy a better line than this, if there is one.  

I've ordered the cannister filter, still trying to find little fuel proof crimps. The guy at O'Reilly's tried to sell me some Dorman heat shrink tubing that was way too big to seal down on the little Walbro connector wires.

Jack the R wrote:

I've ordered the cannister filter, still trying to find little fuel proof crimps.  The guy at O'Reilly's tried to sell me some Dorman heat shrink tubing that was way too big to seal down on the little Walbro connector wires.  

A smaller version of this: https://www.amazon.com/Gardner-Bender-AMT-124-Environment-Heat-Shrink/dp/B000BVZB8E -- it has a goop inside that seals it up when you heat-shrink it after crimping. When you search around you'll find connectors like these: https://www.amazon.com/Sopoby-Connectors-Electrical-Waterproof-Automotive/dp/B01DPS8DPM and others that should work. Take your pick.

Albertj

The wires you can solder and heat shrink which i'd do over crimping in there. I add little hose clamps to the main feed line for insurance. I've never used any on the venturi line - never lost one - I don't think I've ever gotten one off the bucket end. It's really on there and not the easiest to get to with your hands. But if you get it forced on you should be good. Ive never really used them myself but one of those once-and-for-all metal clamps like whats on the CV boots would be good insurance

If you pm your address, I can ship you a generous length of new clear tubing at the cost of shipping to try.

turtleman wrote:

The wires you can solder and heat shrink which i'd do over crimping in there. I add little hose clamps to the main feed line for insurance. I've never used any on the venturi line - never lost one - I don't think I've ever gotten one off the bucket end. It's really on there and not the easiest to get to with your hands. But if you get it forced on you should be good. Ive never really used them myself but one of those once-and-for-all metal clamps like whats on the CV boots would be good insurance

If you pm your address, I can ship you a generous length of new clear tubing at the cost of shipping to try.

Good point, Codith... One link I posted points to connectors that solder from heat shrink level heat. Instructions come with the connectors so I did not elaborate. Myself, I'd prefer to crimp then solder and then cover joint with heat shrink and compound. The reason is that on a good crimp the metals form a colloidial bond at their interface. Soldering afterward, however, keeps corrosion out of the crimp (who hasn't seen a corroded crimp?) Tune up grease or silicone caulk will work as compound to cover the joint, among other things. The excess just squirts out from the heat shrinking.

Is it possible to re-pin the Walbro connector?

The big problem I'm having ATM is getting the main fuel line onto the cannister nipple.